The presently disclosed embodiments relate generally to layers that are useful in imaging apparatus members and components, for use in electrophotographic, including digital printing, apparatuses. More particularly, the embodiments pertain to electrophotographic printing apparatus utilizing an improved toner image transfer member comprising a composition used to form an image transferring member component, namely, a single layered seamless intermediate transfer belt. The composition comprises a film forming polycarbonate which provides an intermediate transfer belt with numerous beneficial properties, such as, flexibility, high temperature stability, and superior mechanical strength which extends the service life of the intermediate transfer belt.
In electrophotography or electrophotographic printing, the charge retentive surface, typically known as a photoreceptor, is electrostatically charged, and then exposed to a light pattern of an original image to selectively discharge the surface in accordance therewith. The resulting pattern of charged and discharged areas on the photoreceptor form an electrostatic charge pattern, known as a latent image, conforming to the original image. The latent image is developed by contacting it with a finely divided electrostatically attractable powder known as toner. Toner is held on the image areas by the electrostatic charge on the photoreceptor surface. Thus, a toner image is produced in conformity with a light image of the original being reproduced or printed. The toner image formed on the photoreceptor surface may then be transferred to a receiving substrate or support member (e.g., paper) directly or first through the use of an intermediate transfer member, and the image affixed thereto to form a permanent record of the image to be reproduced or printed followed by transferring it to the receiving paper for fussing into copy printout. Subsequent to development, excess or residue toner left on the charge retentive surface is cleaned from the surface. The process is useful for light lens copying from an original or printing electronically generated or stored originals such as with a raster output scanner (ROS), where a charged surface may be imagewise discharged in a variety of ways.
The foregoing generally describes black and white electrophotographic printing machines. Electrophotographic printing can also produce color images by repeating the above process for each color of toner that is used to make the color image. For example, the photoreceptive surface may be exposed to a light image that represents a first color, say black. The resultant electrostatic latent image can then be developed with black toner particles to produce a black toner layer that is subsequently transferred onto a receiving substrate. The process can then be repeated or a second color, say yellow, then for a third color, say magenta, and finally for a fourth color, say cyan. When the toner layers are placed in superimposed registration the desired composite color toner image is formed and fused on the receiving substrate.
The color printing process described above superimposes the color toner layers directly onto a substrate. Other electrophotographic printing systems use intermediate transfer belts. In such systems successive toner layers are electrostatically transferred in superimposed registration from the photoreceptor onto an intermediate transfer belt. Only after the composite toner image is formed on the intermediate transfer belt is that image transferred and fused onto the substrate. Indeed, some electrophotographic printing systems use multiple intermediate transfer belts, transferring toner to and from belts as required to fulfill the requirements of the machine's overall architecture.
In operation, an intermediate transfer belt is brought into contact with a toner image-bearing member such as a photoreceptor belt. In the contact zone an electrostatic field generating device such as a corotron, a bias transfer roller, a bias blade, or the like creates electrostatic fields that transfer toner onto the intermediate transfer belt. Subsequently, the intermediate transfer belt is brought into contact with a receiver. A similar electrostatic field generating device then transfers toner from the intermediate transfer belt to the receiver. Depending on the system, a receiver can be another intermediate transfer member or a substrate onto which the toner will eventually be fixed. In either case the control of the electrostatic fields in and near the transfer zone is a significant factor in toner transfer.
Intermediate transfer belts often take the form of seamed belts fabricated by fastening two ends of a web material together, such as by welding, sewing, wiring, stapling, or gluing. Belts, sheets, films and the like are important to the xerographic process. Belt function is often significantly affected by the seam of the belt. For example, belts formed according to known butting or overlapping techniques provide a bump or other discontinuity in the belt surface leading to a height differential between adjacent portions of the belt, for example, of 0.010 inches or more depending on the belt thickness. This increased height differential leads to performance failure in many applications. When overlapping the opposite ends of a rectangular cut sheet and ultrasonically welded into a seamed intermediate transfer belt, the seam of the flexible intermediate transfer belt may occasionally contain undesirable high protrusions such as peaks, ridges, spikes, and mounds. These seam protrusions present problems during image cycling of the belt machine because they interact with cleaning blades to cause blade wear and tear, which ultimately affect cleaning blade efficiency and service life.
Another major disadvantage of having a seam in the flexible intermediate transfer belt is that the seam is a non imageable area due to physical/morphological discontinuity and electrical variation from the bulk of the belt, so it causes print defects in copy image printout.
To avoid the above problems, seamless intermediate transfer belts are preferred instead. In addition, the entire belt surface of the seamless intermediate transfer belt is imageable area without the complications caused by the seamed region of seamed belts. However, these seamless require manufacturing processes that are more involved and/or expensive than similar seamed intermediate transfer belts. This is particularly true when the intermediate transfer belt is long.
Due to the usage demands on the imaging member systems, the component parts are subject to significant wear which negatively impacts performance and service life. Thus, there is a constant need for improving such systems and parts, such as intermediate transfer belt in particular, to provide good performance and extended service life. In particular, there is a need for an efficient method of providing a seamless belt with improved properties and low cost.
Prior conventional intermediate transfer belts are disclosed in U.S. Pat. Nos. 6,101,360 and 6,044,243, which are hereby incorporated by reference in their entireties. The term “photoreceptor” or “photoconductor” is generally used interchangeably with the terms “imaging member.” The term “electrophotographic” includes “electrophotographic” and “xerographic.” The terms “charge transport molecule” are generally used interchangeably with the terms “hole transport molecule.”